Patent GB-1225163-A (GB)
IPC: H04N7/14
Filed: 1968-03-29
Abstract: 1,225,163. Television. WESTERN ELECTRIC CO. Inc. 29 March, 1968 [4 April, 1967], No. 15118/68. Heading H4F. In a two-way television-telephone system the display C.R.T. is surrounded by a frame-like structure having at least two distinctive surfaces so arranged that when the user is correctly positioned wholly within the field of view of the associated television camera at least one of the distinctive surfaces around the display is not visible, and when the user is partially or wholly outside the field of view of the camera at least part of at least one of those surfaces which were not visible to the user when positioned wholly within the field of view of the camera, are rendered visible. Thus the user when viewing the display C.R.T. may by observation of the distinctive surfaces correctly position himself in the field of view of the camera. In a first embodiment, Figs. 1 and 2, a television-telephone set including a vidicon camera 11 and a display device 12 is provided with an alignment apparatus 14 disposed in a recess between the front surface of the cabinet 10 and the front of display device 12, and comprising two frame-like members 16, 17 separated by a band 18 the interior surface 15 of which is distinctively patterned. When the subscriber is properly aligned surface 15 is not visible, but if the subscriber is misaligned vertically and/or laterally parts of surface 15 will be visible. Surface 15 may include variously coloured strips to enable the subscriber to determine how far off-centre he is. In a second embodiment, Fig. 5, which gives in addition to a visual centering indication, an indication of the acceptable operating distance from the camera, a truncated wedge-like frame 35 is provided around the display, both the interior surface 26a, 26b and the exterior surface 25a, 25b, providing the indication. Both these surfaces are invisible when the subscriber is positioned in region 75a. Variation in camera angle is necessary to accommodate people of different heights and thus it is desirable to vary the indication of vertical alignment to coincide with a variation in camera angle. This may be effected by pivoting the top and bottom portions of the truncated wedge-like frame (Fig. 7, not shown) so that the correct position of the subscriber is moved from position 40 upwards or downwards in plane 41, Fig. 5. In another arrangement in which the indication of proper vertical alignment is variable, surfaces 100a and 100b, Fig. 8, are angled to define the maximum camera field G for the subscriber, and sliding-members 103 and 104 are coupled mechanically to each other and to the camera and move in synchronism. Members 103 and 104 are used to restrict the background areas 101 and 102 visible to the subscriber, the surfaces of members 103 and 104 and surfaces 1 and 100b being similarly coloured while the background area 101, 102 is distinctively coloured. Proper alignment is indicated when only the background areas 101 and 102 are visible to the subscriber, members 103 and 104 being positioned depending upon the height of the subscriber. The truncated wedge-like frame of Fig. 5 may form part of a protective shield for the C.R.T. display, or it may comprise a decorative offset in the surface of the cabinet.